1. Field of the Invention
The present invention relates to a mirror replacement system for a vehicle, in particular for a commercial vehicle.
2. Description of the Related Art
In motor vehicles, so-called fields of view are legally-prescribed based on the type of motor vehicle, for example, motorcycles, motor vehicles for transporting passengers, motor vehicles for transporting goods, etc. The fields of view must be provided by a device for indirect viewing and must be viewable at all times by the driver sitting in the driver's seat using the device for indirect viewing. Depending on the type of vehicle and, in particular, on which areas around the vehicle can be directly viewed by the driver, different legal provisions require that certain fields of view are permanently and reliably viewable at all times using the devices for indirect viewing. In Europe, the fields of view which have to be reliably visible for a driver all times are defined in the UN/ECE Regulation No. 46 which is further described below. Other relevant regulations include e.g. ISO 16505.
For commercial vehicles, such as, for example, trucks or delivery vehicles, a primary mirror is currently provided on each of the driver's side and the passenger's side as the device for indirect viewing. By using the primary mirror, the vehicle driver can see a level and horizontal part of the road surface of a certain width that extends from a stipulated distance behind the vehicle driver's eye points up to the horizon. In addition, a band of larger width must be viewable for the vehicle driver using this mirror, which band begins at a short distance behind the driver's eye points. Such legally-prescribed areas, which must be viewable permanently and at all times by the driver with the use of the devices for indirect viewing, will be designated as fields of view.
Currently, according to the field of view of Class II of UN/ECE Regulation No. 46, the field of view of the exterior rear-view mirror (primary mirror) on the driver's side and the exterior rear-view mirror on the passenger's side must be adapted such that the driver can see at least a 4 m wide, flat, horizontal portion of the road, which is bounded by a plane parallel to the median longitudinal vertical plane and passing through the outermost point of the vehicle on the driver's side and the passenger's side of the vehicle, respectively, and which extends from 20 m behind the driver's eye (ocular points) to the horizon. In addition, the road must be visible to the driver over a width of 1 m, which is bounded by a plane parallel to the median longitudinal vertical plane and passing through the outermost point of the vehicle starting from a point 4 m behind the vertical plane passing through the driver's eye (ocular points).
In addition to these primary (main) mirrors, fields of view (vision), which are reproduced (shown or depicted) by wide-angle mirrors, are required to be viewable on both sides of the commercial vehicle. An area behind the eye (ocular) points of the driver is viewed with the wide-angle mirrors in a certain length in the longitudinal direction of the vehicle; this area is wider than the area viewable by the primary mirror, but only extends a certain length along the vehicle. This area is defined as field of view IV (Class IV) according to the UN/ECE Regulation No. 46.
Currently, according to the field of view of Class IV of UN/ECE Regulation No. 46, the field of view of the “wide-angle” exterior mirror on the driver's side and the “wide-angle” exterior mirror on the passenger's side must be such that the driver can see at least a 15 m wide, flat, horizontal portion of the road, which is bounded by a plane parallel to the median longitudinal vertical plane and passing through the outermost point of the vehicle on the driver's side and the passenger's side of the vehicle, respectively, and which extends from at least 10 m to 25 m behind the driver's eye (ocular points). In addition, the road must be visible to the driver over a width of 4.5 m, which is bounded by a plane parallel to the median longitudinal vertical plane and passing through the outermost point of the vehicle starting from a point 1.5 m behind the vertical plane passing through the driver's eye (ocular points).
Conventionally and as described above, the view into the fields of view is provided with one or more mirrors. However, mirrors have some drawbacks. For example, mirrors only show the driver objects which are one the same side of the mirror as the drivers. Any object behind a mirror cannot be shown by that mirror. Additionally, mirrors made of flat glass only show the driver a small area unless the mirrors are very close to the driver. If they are convex shaped, this creates image distortion. For large vehicles, it is common to have seven or more mirrors mounted around the outside of the vehicle, most of which are distorted and convex, and it is even common for these vehicles to still have blind spots, despite of all the mirrors. Additionally, it is difficult for the driver to pay attention to all relevant mirrors at the same time.
In recent times, it is becoming increasingly common to consider using camera systems as devices for indirect viewing either in addition to or as a replacement for the mirrors as devices for indirect viewing. In such camera systems, an image sensor device continuously captures (detects and stores) an image. The (video-) data captured by the image capturing unit are transmitted, e.g., using a supply unit and optionally after further processing, to a display device located in the driver's cabin. The display device depicts a view into the corresponding legally-prescribed field of view or a plurality of fields of view and optionally supplemental information, such as e.g., possible collision risks, distances to other objects, etc., for the area around the vehicle in manner that is permanently viewable at all times for the driver, while offering a superior night vision, more flexible placement options and larger fields of view with the opportunity for less distortion.
Permanently viewable means in this context that the view into the field of view is depicted in a timely uninterrupted manner, i.e. not interrupted by alternatingly showing and hiding the field of view or parts thereof or by overlaying other representations such that the field of view cannot be seen completely. Accordingly, the respective field of view or the fields of view are continuously and in real time shown on the display device. This holds for all vehicle conditions, in which the ignition is switched on, preferably e.g. coupled to a sensor which receives a corresponding signal, e.g. a door opening signal or an ignition switch signal.
US 2013/0229519 A1 discloses an automatic rear view display which includes a single camera configuration and a dual camera configuration. In the single camera configuration, as soon as an entertainment screen in a ceiling mounted entertainment system is opened or when the driver puts the vehicle in reverse, the view from a first camera proximate to the rear license plate is displayed on the rearview mirror. In the dual camera version, when the entertainment screen is opened, the view from a second camera near the roof of the vehicle is displayed in the rearview mirror. In the dual camera version if the driver puts the vehicle in reverse, with the entertainment screen open or closed, the view from a first camera would be displayed instead. In both versions as soon as the entertainment screen is closed (and the vehicle is not in reverse) the rearview mirror goes back to being a regular mirror.
U.S. Pat. No. 7,463,381 discloses a method which includes selecting a video source view from at least one of a plurality of vehicle-mounted video sources based on detection of a vehicle event. The video source view may be displayed according to a presentation mode. The method may include associating a plurality of vehicle events with a video source view or video presentation mode. A system includes display logic selecting a video source view from a plurality of vehicle mounted video sources based on detection of a vehicle event. The system can include presentation rules specifying an association between a plurality of vehicle events and a video source view and/or a video presentation mode. The presentation rules are editable and configurable.
Modern mirrors create a nearly perfectly sharp picture for a driver. The level of detail available to the driver is dependent on the distance to the object and the eyesight of the driver. With camera systems, the level of detail available is affected by many different parameters: the resolution of the camera sensor, the field of view of the camera, but also the resolution of the monitor, how much of the camera field-of-view is being displayed on the monitor, how far away the monitor is from the driver space, and the eyesight of the driver. In some combinations of those parameters, drivers may be able to zoom in and see far off objects clearly that they would be unable to see in a mirror. In other combinations of those parameters, the driver may be looking at an area with such poor resolution that he fails to identify a dangerous traffic threat.
Further, with mirrors, the driver is able to use this natural depth perception to view the three dimensions in the mirror. This gives the driver a comfortable understanding of his own position relative to the environment of the object in it. The driver does not get depth perception while using camera systems with commonly available two-dimensional displays, which means that the driver must use the visible size of features on the screen to judge both relative position and relative speed. It can be especially difficult to make this judgment, if the driver is allowed to zoom into or out of the image. If the driver is allowed to zoom in and out, he can very easily lose track of how far away objects in the environment are, and this can create dangerous situations in the road.
Further, with mirrors, the driver is able to move his head by leaning and by turning to view different areas. This gives the driver access to a wider field of view, and it also gives the driver a comfortable understanding of where he is looking in the surrounding environment. Camera systems can allow the driver to pan around to see different areas, but the driver uses the physical sensations of leaning and looking, so he may lose track of where exactly he is looking in the environment. This can create a dangerous situation, if the driver misjudges the location of an object in view, or if the driver leaves the camera system showing an irrelevant area of the environment and not showing the important areas.